Items such as vents, ductwork, air conditioning units, and the like commonly protrude from the surface of a roof. The size and location of these items is preferably provided to the factory which creates the membrane. With this information, the factory may make provisions for these items in the membrane.
Providing a water-tight seal around a protrusion in a roof presents a number of problems. U.S. Pat. No. 4,872,296 discloses a method and a fitment which have been used to cover the corners of protrusions. The fitment of this patent comprises a first generally rectangular member segment, a side being part-way split interjacent its ends, and a second member segment with a triangularly-shaped corner portion conformed to loop shape and having its marginal edges overlying portions of the first segment contiguous to the split and being welded thereto in a continuous weld seam. This method and fitment work best when the angle of the corner is a right angle and the angle between the roof and the protrusion is a right angle.
In many cases, however, the corner is not a right angle, the protrusion is not at a right angle to the roof, or there is some other irregularity in the protrusion, such as the bottom and the top being different sizes. In these situations, known fitments and methods do not provide satisfactory results. The membrane must be folded or “bunched” in order to conform the membrane to the underlying structure. The folding and bunching is unsightly, and water may collect in the folds which may have deleterious effects on the roofing membrane and/or may lead to localized leaks at seams and at other places in the membrane. In addition, folding can lead to cracking of the roof membrane over time due in part to stress induced by the fold lines. Therefore, a need exists for an adjustable fitment and roof membrane system that provides a smooth transition no matter what the shape or angle of the underlying protrusion and that eliminates the need to fold or bunch the fitment or the roof membrane.
U.S. Pat. No. 6,199,326 provides an embodiment of an adjustable roof membrane which includes a universal fitment. The disclosure of U.S. Pat. No. 6,199,326 is hereby incorporated by reference in its entirety. In this embodiment, the universal fitment is an adjustable corner fitment for a roof. The adjustable corner fitment is comprised of a top membrane and a bottom membrane. The top membrane has a cutout. The cutout extends from a side of the top membrane. The base membrane portion has a first side, a second side, a third side and a fourth side. The first side is connected to the second side at a first angle greater than 90 degrees, and the third side is connected to the fourth side at a second angle greater than 90 degrees. The base membrane portion is conformed to loop shape such that the first side and the second side underlie portions of the top membrane contiguous to the cutout. The first side of the base membrane may be completely welded to the top membrane prior to installation. However, the second side of the base membrane is adjustable relative to the top membrane prior to installation on the roof. Consequently, an installer is able to adjust the corner fitment to a corner in the field to eliminate unnecessary buckling of the corner fitment or the roof membrane. After adjusting the corner fitment to the corner, the installer may then completely weld the second side of the base membrane to the top membrane.
Further, U.S. Pat. Nos. 6,754,993 and 7,347,907 (both issued to Mayle et al.) disclose adjustable roof fitments and are herein incorporated by reference in their entirety. The fitments and methods for constructing the fitments disclosed in these patents are useful with roof membranes to cover exposed roof areas around a vertical protrusion in a roof. The fitments may be partially secured to a roof membrane, a boot, and/or a spanning strip prior to being positioned at the corner of a vertical protrusion. Alternatively, the fitment may be positioned independently of the other components at the corner of a vertical protrusion. After the fitment is positioned at the corner of a vertical protrusion, a floating portion of the fitment may be adjusted to fit the corner of the vertical protrusion so that there is minimal or no folding or bunching of the material of the fitment. In this adjusted position, the floating portion of the fitment may be dielectically welded, hot air bonded or otherwise secured to another portion of the fitment, and the fitment may be finally dielectrically welded, hot air bonded or otherwise secured to the roof membrane, the boot, and/or the spanning strips.
These prefabricated roofing fitments may be made from thermoplastic olefin (TPO), polyvinyl chloride (PVC), or any other suitable material. TPO material is much less expensive than other roof membrane material, but has not been used in the roofing industry in the past because TPO is non-conductive material and therefore, cannot be dielectrically welded. Material such as polyvinyl chloride (PVC) has been commonly used in the roofing industry since it can be easily dielectrically welded. However, PVC is much more expensive than TPO. Accordingly, PVC lends itself to dielectric welding or hot air bonding, while TPO lends itself to hot air bonding. With the hot air bonding apparatus and methods of the exemplary embodiment a fully TPO fitment is achieved.
An exemplary embodiment may utilize any material suitable for constructing the fitments described herein. Examples of the materials utilized in the fitments may be comprised of polyvinyl chloride (PVC), thermoplastic olefin (TPO), or rubber, and any mixtures thereof. The fitments may be made from or use any material that is heat bondable, glue bondable, or solvent bondable. The fitments may be made with or use a material that is compatible with dielectric welding, hot air bonding, solvent fusion, adhesive bonding, heat welding, melt bonding, vibration welding, ultrasonic welding, heat staking, or other methods commonly known to those experienced in the field of this art.
In addition to the novel features and advantages mentioned above, other objects and advantages are achieved, at least in the preferred embodiments, by the invention as shown and described below.